This disclosure relates to a high voltage igniter module used to ignite a lamp, for example a HID (High Intensity Discharge) lamp. Specifically, the disclosure relates to the mechanical design of a high voltage transformer and the associated igniter module.
Conventionally, high voltage igniter circuits are used to start HID lamps. One example of a HID lamp requiring a high voltage ignition is an automotive lamp commonly referred to as a head light. To produce the high voltage ignition signal, an igniter circuit is operatively connected to the HID lamp. Conventional configurations of an automotive headlamp assembly include an igniter circuit housed within the HID lamp assembly, the igniter circuit including a pc board and a transformer. The igniter printed circuit board carries electrical components to produce a high voltage ignition signal. In addition, the pc board provides electrical connection points to power the ignition circuit and deliver the high voltage ignition signal to a HID lamp.
One example of a conventional embodiment of a high voltage igniter circuit includes a lamp receptacle mounted to the igniter circuit pc board. In addition, it is common to mount the igniter circuit transformer either directly to the pc board or separate from the pc board. In the later case, the transformer may be mounted to the lamp housing where the pc board provides the necessary winding connection points.
As previously indicated, this disclosure relates to the mechanical design of the igniter module transformer. Conventionally, high voltage igniter transformers have been used to produce the high voltage signals necessary to provide an ignition signal. In general, the igniter transformer includes a magnetic core, a secondary winding surrounding the magnetic core and a primary winding surrounding the secondary core. The output voltage associated with the secondary winding is related to the ratio of the number of secondary windings to the number of primary windings.
During the assembly of a HID lamp, it is common practice to pot the transformer with an insulating material to provide electrical insulation of the windings from other electrical components contained within the lamp housing. In addition, potting of the transformer increases the overall stability of the transformer's performance. One drawback associated with potting of the transformer is the necessary step of characterization of the transformer subsequent to potting.
Conventionally, the characterization of an igniter transformer occurs after the igniter module has been fully assembled or the transformer has been mounted within a lamp housing chamber separate from the pc board. In the first case, the igniter pc board carries all electrical components associated with the igniter circuit, including the transformer. Subsequent to the assembly of the pc board, the pc board is potted. Characterization of the transformer is performed with the transformer mounted and potted on the completed pc board assembly. In the event the characterization of the potted igniter transformer is not within the required specifications, the entire pc board is discarded or extensive rework is required to remove the potting material to replace the transformer.
In the second case, the igniter transformer is mounted and potted within a separate chamber of the lamp housing. The transformer is characterized subsequent to mounting and potting within the lamp housing. In the event the characterization of the igniter transformer is not within the required specification, the housing and transformer assembly are discarded or extensive rework is required to remove the potted transformer from the housing to replace the transformer.
This disclosure provides an igniter module and associated transformer to enable characterization of the transformer prior to the assembly of the transformer within the lamp housing or mounting of the transformer to an igniter pc board. The disclosed igniter module eliminates the need to discard/rework a pc board or housing as previously discussed if the characterization of an igniter transformer is determined to be out of specification subsequent to potting.